Patching of dictionaries should be case sensitive on keys

[kichalla]

The current code handles all (dynamic(example: ExpandoObject implements IDictionary<string,object>) or not) dictionaries which implement IDictionary<string, object> in a case Insensitive way. This is an incorrect behavior.

For example:

1. When Json.net deserializes data into a regular IDictionary<,> it considers the keys case-sensitive.
2. When Json.net deserializes data into a regular Poco type, it considers the property names case-Insensitive.

Considering the above behavior, we should do the following in json patch:

1. For dynamic types (like ExpandoObject, DynamicObject etc.), the matching of keys should be case-Insensitive. This is to keep the behavior consistent with a Poco type where the property names are considered case-Insensitive.
2. For dictionaries, keep the default json.net behavior, i.e. keep them case sensitive.

@dougbu @rynowak

[Eilon]

@kichalla can you link to the PR/commit where you previously fixed this and then close this? Thanks!

[kichalla]

81931e7